Changes
/* Trick */
==== Trick ====
''rules for the nomination of variables or functions'':
* A name of V/F don't begin by a number
* A name of V/F don't begin by a mathemtics symbole (+ / -...) or a '*' or '.'
* A name of V/F don't begin or include a num '-' or ' ' '
=== chapter 4 (résumé) ===
